Does food quality control the distribution of cold-water corals?

ATLAS work package 2 presentation at ATLAS 3rd General Assembly

A number of environmental factors have been considered important in controlling the distribution of the heterotrophic scleractinid cold-water coral, Lophelia pertusa, and its associated ecosystem, including temperature, sea-bed substratum, slope, hydrography, current speeds, suspended sediment or particulate organic matter supply. The recent discovery of thriving colonies of L. pertusa living on near vertical cliff walls in the Whittard Canyon (Celtic Sea) has extended the occurrence of the species beyond the optimal density envelope identified for previously known cold-water coral (CWC) colonies in the North-Eastern Atlantic. We hypothesize that the chemical composition or food quality of suspended particulate organic matter (sPOM) plays an important role in the presence/absence of L. pertusa. Analyses of the lipid composition of sPOM collected at 111 sites in the North Eastern Atlantic Ocean, combined with previously reported video/still evidence of CWC occurrence allow us to address our hypothesis. Multivariate statistical analyses confirm that the CWC occurs where there is varied diet, but that the essential highly unsaturated fatty acids eicosapentenoic and doeicosahexenoic acids (EPA and DHA, respectively) and dominantly labile algal-derived compounds are important markers for the composition of sPOM that appears to favour the occurrence of L. pertusa.